1. Field of the Invention
The present invention relates to a circuit arrangement for telecommunications systems, particularly telephone switching systems, comprising an information interrogating device which cyclically drives a plurality of inquiry locations, these information interrogating devices driving the inquiry locations to solicit information which may be present under given conditions with different interrogation frequencies with respect to the various inquiry locations and respectively modifying the interrogation frequency with respect to an inquiry location dependent on the appearance of an information to be solicited. It further comprises interrogation memories assigned to the information interrogating devices in which the individual number of drive events within a respective overall drive cycle covering all inquiry locations is individually stored for each of the inquiry locations, whereby the individual plurality of drive events is stored in the interrogation memory for each of the inquiry locations by way of a corresponding one-time (or repeated) storing of their respective addresses at a corresponding number of memory locations which are distributed within the cyclical sequence of the totality of memory locations, regularly distributed and successively read following one another.
2. Description of the Prior Art
A circuit arrangement of the type set forth above is disclosed in the German published application No. 3,443,616, and enables inquiry locations to be interrogated with a different frequency. Inquiry locations can be individual scan points, for example, in subscriber-associated switching devices, such as connector sets or subscriber line circuits. This is set forth in terms of further details in, for example, the German published application No. 2,748,795. Incoming switch identifiers are recognized in that the interrogation events undertaken at a scan point proceeding from a certain time acquire different interrogation results than previously, in particular, for the duration of the switch identifier. In this context, the German published application No. 2,748,795 discloses that, for example, selection pulses output by subscriber stations arrive in connector sets. The scan points are normally sensed in a relatively slow tempo. When the beginning of a selection pulse is recognized by way of an interrogation event, then the relatively slow interrogation tempo is replaced by a relatively fast interrogation tempo. In an arrangement as set forth in the German published application No. 2,748,795, the possibility is therefore created of acquiring the end of a respective selection pulse and, therefore, the duration of the appertaining selection pulse as accurately as possible in chronological terms. In this manner, for example, selection pulses and switch identifiers formed by pulses having a different duration can be distinguished from one another with great reliability.
When, in this last-mentioned case, an interrogation result indicating a pulse beginning is identified, then the interrogation tempo therefore changes from a relatively slow sequence to a relatively fast sequence. When, in a second interrogation event (or in the third interrogation event) a further interrogation result of the same content is identified after an interrogation result indicating a pulse beginning, then it is seen therefrom that this, in fact, did not involve a pulse beginning, but a disturbance. For the further interrogation events, the interrogation tempo in response thereto is, in turn, changed from the relatively fast sequence to the slow sequence.
In the case known from the last-mentioned German published application, the change of the interrogation tempo serves the purpose of increasing the interrogation capacity of an interrogating device by slowing the interrogating tempo in that the number of inquiry locations can thereby likewise be increased to a corresponding degree, whereby a relatively chronologically accurate acquisition of switch identifiers having a defined and individual duration is nonetheless guaranteed. When, however, it is not a matter of a cyclical scanning of scan points for the acquisition of switch identifiers by distinguishing the switch identifier from the alternate switching state (for example, pulse pause and "interselection time") but is a matter of a soliciting complete information from individual inquiry locations, then a different problem comes to fore. The occurrence of information to be solicited can be extremely different at different inquiry locations. If the various inquiry locations are cyclically uniformly driven, then there can be inquiry locations at which the information to be solicited back up, whereas there are other inquiry locations at which the information solicited are only sporadically present when they are driven and interrogated. In comparison to the principle of cyclical scanning, the principle of driving inquiry locations on the basis of individual output request present signals is also known in this context. However, the outlay which must be expended for generating, outputting, transmitting, accepting and evaluating these request present signals is disadvantageous, as is the successive processing of these request present signals.
The invention therefore proceeds from a circuit arrangement of the type set forth above wherein the various inquiry locations are cyclically driven.
In circuit arrangements of the type specified, it can then occur that the occurrence of information to be solicited at the various inquiry locations is not only unequal, but is also subject to fluctuations per inquiry location, and that a discontinuous change in the multitude of information to be solicited can occur at individual inquiry locations. In order to counter this problem, the German published application No. 3,443,616 proposes a circuit arrangement in which it is provided that an information interrogating device, sequencing in successive interrogation cycles, assigns and stores cycle numbers for the inquiry locations for the assignment of interrogation frequencies for these inquiry locations, the cycle numbers respectively indicating the number of interrogation cycles at which the appertaining inquiry location is driven respectively once. An inquiry location, accordingly, is interrogated only once in an interrogation cycle or in two or more interrogation cycles, depending on the measure of the respectively stored cycle number. It is also proposed in accordance with this circuit arrangement that every receipt of an information from an inquiry location, the information interrogating device immediately drives this inquiry location again at the next interrogation cycle and either repeats this given another receipt of an information or, in the opposite case, continues the interrogation tempo from this point based on the measure of the cycle number stored for this inquiry location. Accordingly, therefore, the interrogation tempo per inquiry location is increased from an interrogation tempo individually assigned to the appertaining inquiry location to a uniform, maximum interrogation tempo. In addition, it is provided in accordance with the proposed circuit arrangement that the information accepted from the various inquiry locations are counted in time intervals per inquiry location and the cycle numbers are again adapted inversely proportional after each time interval based on the measure of these counter results, for example, by the respective value "1". Accordingly, the cycle numbers stored per inquiry location are dynamically adapted dependent on the actual traffic volume.
Given a circuit arrangement of this type, therefore, a heavier crush of information to be interrogated at an inquiry location therefore effects that this is interrogated in every interrogation cycle instead of being interrogated based on the measure of the respectively stored cycle number. This means that this inquiry locations having a higher volume of information to be interrogated at the time are interrogated with equal frequency. A greater crush of information to be interrogated at all inquiry locations would result in all inquiry locations being interrogated with equal frequency. As a result thereof, the effect of having the different inquiry locations interrogated with different frequencies which is produced by the cycle numbers stored per inquiry location would be completely canceled precisely in those times of particularly high volume of information to be interrogated.